[mutter] window: Set fall-back tile monitor if not set

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 033f0d11bfd87f82cbd3ffc56b97574bb3ffb691
Author: Jonas Ådahl <jadahl gmail com>
Date:   Thu Apr 2 19:05:21 2020 +0200

    window: Set fall-back tile monitor if not set
    
    When tiling, we want to set the tile monitor. To not have to do this
    from the call site, make meta_window_tile() fall back to the current
    monitor if nothing set it prior to the call.
    
    This will make it more convenient for test cases to test tiling
    behavior.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1171

 src/core/window.c | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/src/core/window.c b/src/core/window.c
index a6b3110e1..75012ed6c 100644
--- a/src/core/window.c
+++ b/src/core/window.c
@@ -3156,6 +3156,10 @@ meta_window_tile (MetaWindow   *window,
       window->tile_monitor_number = -1;
       return;
     }
+  else
+    {
+      window->tile_monitor_number = window->monitor->number;
+    }
 
   if (window->tile_mode == META_TILE_MAXIMIZED)
     directions = META_MAXIMIZE_BOTH;